Build Log4cxx library.Official MinGW g++-3.4.5 doesn't support wide string, we need to disable them with --disable-wchar_t. Some unofficial MinGW with wide string support can be found (ogre/g++-3.4.5 or develer/g++-4.1.2), but we avoid them until official MinGW GCC 4.2.0 release (soon):